Threshold-driven optimization for reference-based auto-planning.

abstract：:In recent years, the Monte Carlo method has been used in a large number of research studies in radiation therapy. For applications such as treatment planning, it is essential to validate the dosimetric accuracy of the Monte Carlo simulations in heterogeneous media. The AAPM Report no 105 addresses issues concerning cl...

journal_title：Physics in medicine and biology

authors： Titt U,Sahoo N,Ding X,Zheng Y,Newhauser WD,Zhu XR,Polf JC,Gillin MT,Mohan R

更新日期：2008-08-21 00:00:00

abstract：:The current UK code of practice for high-energy photon therapy dosimetry (Lillicrap et al 1990 Phys. Med. Biol. 35 1355-60) gives instructions for measuring absorbed dose to water under reference conditions for megavoltage photons. The reference conditions and the index used to specify beam quality require that a mach...

journal_title：Physics in medicine and biology

authors： Thomas SJ,Aspradakis MM,Byrne JP,Chalmers G,Duane S,Rogers J,Thomas RA,Tudor GS,Twyman N,IPEM Working Party.

更新日期：2014-03-21 00:00:00

abstract：:Respiratory motion in emission tomography leads to reduced image quality. Developed correction methodology has been concentrating on the use of respiratory synchronized acquisitions leading to gated frames. Such frames, however, are of low signal-to-noise ratio as a result of containing reduced statistics. In this wor...

journal_title：Physics in medicine and biology

authors： Lamare F,Ledesma Carbayo MJ,Cresson T,Kontaxakis G,Santos A,Le Rest CC,Reader AJ,Visvikis D

更新日期：2007-09-07 00:00:00

abstract：:Fluorescence diffuse optical tomography (fDOT) provides 3D images of fluorescence distributions in biological tissue, which represent molecular and cellular processes. The image reconstruction problem is highly ill-posed and requires regularisation techniques to stabilise and find meaningful solutions. Quadratic regul...

journal_title：Physics in medicine and biology

authors： Correia T,Koch M,Ale A,Ntziachristos V,Arridge S

更新日期：2016-02-21 00:00:00

abstract：:The dosimetric impact of intrafraction prostate motion was investigated for helical tomotherapy treatments. Measured motion tracks were used to calculate the dosimetric impact on delivered target dose distributions. A dynamic dose calculation engine was developed to facilitate this evaluation. It was found that the D9...

journal_title：Physics in medicine and biology

authors： Langen KM,Lu W,Ngwa W,Willoughby TR,Chauhan B,Meeks SL,Kupelian PA,Olivera G

更新日期：2008-12-21 00:00:00

abstract：:In recent years, optical techniques based on diffusion approximation have demonstrated their ability to gain rich spectral information about bone. However, these methods normally assume homogeneity, while cancellous bone and marrow form a highly heterogeneous two-phase medium. This paper studies the limitations of thi...

journal_title：Physics in medicine and biology

authors： Margallo-Balbás E,Taroni P,Pifferi A,Koolstra JH,v Ruijven LJ,French PJ

更新日期：2010-09-07 00:00:00

abstract：:We compare two different implementations of a 3D SPECT system model for iterative reconstruction, both of which compensate for non-uniform photon attenuation and depth-dependent system response. One implementation performs fast rotation of images represented using a basis of rectangular voxels, whereas the other repre...

journal_title：Physics in medicine and biology

authors： Yendiki A,Fessler JA

更新日期：2004-06-07 00:00:00

abstract：:We propose a hybrid multiobjective (MO) evolutionary optimization algorithm (MOEA) for intensity-modulated radiotherapy inverse planning and apply it to optimize the number of incident beams, their orientations and intensity profiles. The algorithm produces a set of efficient solutions, which represent different clini...

journal_title：Physics in medicine and biology

authors： Schreibmann E,Lahanas M,Xing L,Baltas D

更新日期：2004-03-07 00:00:00

abstract：:In (19)F MRI oximetry, a method used to image tumour hypoxia, perfluorocarbons serve as oxygenation markers. The goal of this study is to evaluate the impact of perfluorocarbon distribution and concentration in (19)F MRI oximetry through a computer simulation. The simulation studies the correspondence between (19)F me...

journal_title：Physics in medicine and biology

authors： Baete SH,Vandecasteele J,De Deene Y

更新日期：2011-04-21 00:00:00

abstract：:In radiofrequency (RF) ablation or hyperthermia, internal temperature measurements and tissue property imaging are important to control their outputs and assess the treatment effect. Recently, magnetic resonance electrical impedance tomography (MREIT), as a non-invasive imaging method of internal conductivity distribu...

journal_title：Physics in medicine and biology

authors： Oh TI,Kim HJ,Jeong WC,Chauhan M,Kwon OI,Woo EJ

更新日期：2013-04-21 00:00:00

abstract：:To investigate the detection performance of our automated detection scheme for clustered microcalcifications on mammograms, we applied our computer-aided diagnosis (CAD) system to the database of the Mammographic Image Analysis Society (MIAS) in the UK. Forty-three mammograms from this database were used in this study...

journal_title：Physics in medicine and biology

authors： Ibrahim N,Fujita H,Hara T,Endo T

更新日期：1997-12-01 00:00:00

abstract：:Positron emission tomography is one of the most mature techniques for monitoring the particles range in hadron therapy, aiming to reduce treatment uncertainties and therefore the extent of safety margins in the treatment plan. In-beam PET monitoring has been already performed using inter-spill and post-irradiation dat...

journal_title：Physics in medicine and biology

authors： Kostara E,Sportelli G,Belcari N,Camarlinghi N,Cerello P,Del Guerra A,Ferrero V,Fiorina E,Giraudo G,Morrocchi M,Pennazio F,Pullia M,Rivetti A,Rolo MD,Rosso V,Wheadon R,Bisogni MG

更新日期：2019-01-21 00:00:00

abstract：:An efficient registration strategy is described that aims to help solve delicate medical imaging registration problems. It consists of running several registration methods for each dataset and selecting the best one for each specific dataset, according to an evaluation criterion. Finally, the quality of the registrati...

journal_title：Physics in medicine and biology

authors： Tacchella JM,Roullot E,Lefort M,Cohen ME,Guillevin R,Petrirena G,Delattre JY,Habert MO,Yeni N,Kas A,Frouin F

更新日期：2014-11-21 00:00:00

abstract：:Until now, no matrix transducer has been realized for 3D transesophageal echocardiography (TEE) in pediatric patients. In 3D TEE with a matrix transducer, the biggest challenges are to connect a large number of elements to a standard ultrasound system, and to achieve a high volume rate (>200 Hz). To address these issu...

journal_title：Physics in medicine and biology

authors： Bera D,Raghunathan SB,Chen C,Chen Z,Pertijs MAP,Verweij MD,Daeichin V,Vos HJ,van der Steen AFW,de Jong N,Bosch JG

更新日期：2018-03-29 00:00:00

abstract：:A method will be described for determining the centre of rotation of a mechanically scanned reflection ultrasound computed tomography system. It is based on the principle of obtaining opposing images of a test object containing many point targets. The method is automatic in the sense that the centre of rotation is cal...

journal_title：Physics in medicine and biology

authors： Jago JR

更新日期：1994-12-01 00:00:00

abstract：:Polymer gel dosimetry aims to provide three-dimensional images of radiation therapy dose distributions in irradiated aqueous gels. The first gels required manufacture in an oxygen-free environment, but later the MAGIC formulation was introduced, which could be made in normal atmospheric conditions. Here we report our ...

journal_title：Physics in medicine and biology

authors： Luci JJ,Whitney HM,Gore JC

更新日期：2007-05-21 00:00:00

abstract：:This study looks at blood flow in four different human right coronary arteries (RCAs), which have been reconstructed from bi-plane angiograms. A generalized power-law model of blood viscosity is used to study the blood flow at a particular point in the cardiac cycle. Large differences are found in the wall shear stres...

journal_title：Physics in medicine and biology

authors： Johnston BM,Johnston PR

更新日期：2007-05-07 00:00:00

abstract：:Coincidence resolving time (CRT) is one of the most important physical-performance measures for positron emission tomography (PET), as reconstruction with accurate time-of-flight information enhances the lesion detectability in patient studies. Accordingly, various PET detector designs and high-performance front-end r...

journal_title：Physics in medicine and biology

authors： Park H,Lee S,Ko GB,Lee JS

更新日期：2018-12-10 00:00:00

abstract：:It is well known that the experimental dosimetry of brachytherapy sources presents a challenge. Depending on the particular-dosimeter used, measurements can suffer from poor spatial resolution (ion chambers), lack of 3D information (film) or errors due to the presence of the dosimeter itself distorting the radiation f...

journal_title：Physics in medicine and biology

authors： McJury M,Tapper PD,Cosgrove VP,Murphy PS,Griffin S,Leach MO,Webb S,Oldham M

更新日期：1999-10-01 00:00:00

abstract：:In a previous paper, we described quality assurance procedures for Hi-Art helical tomotherapy machines. Here, we develop further some ideas discussed briefly in that paper. Simple helically generated dose distributions are modelled, and relationships between these dose distributions and underlying characteristics of H...

journal_title：Physics in medicine and biology

authors： Fenwick JD,Tomé WA,Kissick MW,Mackie TR

更新日期：2005-04-07 00:00:00

abstract：:The interest in positron emission tomography (PET) and particularly in hybrid integrated PET/CT systems has significantly increased in the last few years due to the improved quality of the obtained images. Nevertheless, one of the most important limits of the PET imaging technique is still its poor spatial resolution ...

journal_title：Physics in medicine and biology

authors： Rapisarda E,Bettinardi V,Thielemans K,Gilardi MC

更新日期：2010-07-21 00:00:00

abstract：:Fast calculation or simulation of the ablation zone induced by radiofrequency ablation (RFA) has a critical role in hepatic RFA planning and therapy. However, it remains challenging to approximate the ablation zone in real time, especially when more than one probe is involved in one ablation session. This paper presen...

journal_title：Physics in medicine and biology

authors： Chen R,Zhang J,Kong D,Lou Q,Lu F

更新日期：2021-01-27 00:00:00

abstract：:Recently, the initial 2D physical characterization of a small-diameter positron emission tomograph, designed specifically for scanning of small laboratory animals, was reported. The physical characteristics of the tomograph operating in 3D mode have now been measured and compared to those obtained in 2D mode. In 3D, t...

journal_title：Physics in medicine and biology

authors： Bloomfield PM,Myers R,Hume SP,Spinks TJ,Lammertsma AA,Jones T

更新日期：1997-02-01 00:00:00

abstract：:Large volume tissue-equivalent proportional counters are of interest in radiation protection metrology, as the sensitivity in terms of counts per unit absorbed dose in these devices increases as the square of the counter diameter. Conventional solutions to the problem of maintaining a uniform electric field within a c...

journal_title：Physics in medicine and biology

authors： Verma PK,Waker AJ

更新日期：1992-10-01 00:00:00

abstract：:The probability of a photon (x-ray, gamma-ray, bremsstrahlung, etc) of a given energy E undergoing absorption or scattering when traversing a layer of material Z can be expressed quantitatively in terms of a linear attenuation coefficient mu (cm(-1)). Since mu is dependent on the material's density, rho (g cm(-3)), wh...

journal_title：Physics in medicine and biology

authors： Hubbell JH

更新日期：1999-01-01 00:00:00

abstract：:Microbeam radiation therapy (MRT) is a treatment approach in radiation therapy where the treatment field is spatially fractionated into arrays of a few tens of micrometre wide planar beams of unusually high peak doses separated by low dose regions of several hundred micrometre width. In preclinical studies, this treat...

journal_title：Physics in medicine and biology

authors： Debus C,Oelfke U,Bartzsch S

更新日期：2017-10-19 00:00:00

abstract：:Intraoperative x-ray radiography/fluoroscopy is commonly used to assess the placement of surgical devices in the operating room (e.g. spine pedicle screws), but qualitative interpretation can fail to reliably detect suboptimal delivery and/or breach of adjacent critical structures. We present a 3D-2D image registratio...

journal_title：Physics in medicine and biology

authors： Uneri A,De Silva T,Goerres J,Jacobson MW,Ketcha MD,Reaungamornrat S,Kleinszig G,Vogt S,Khanna AJ,Osgood GM,Wolinsky JP,Siewerdsen JH

更新日期：2017-04-21 00:00:00

abstract：:A reader study was conducted to tune the parameters of an observer model used to predict the detectability index (dʹ ) of test objects as a task-based quality control (QC) metric for digital mammography. A simple test phantom was imaged to measure the model parameters, namely, noise power spectrum,modulation transfer ...

journal_title：Physics in medicine and biology

authors： Bloomquist AK,Mainprize JG,Mawdsley GE,Yaffe MJ

更新日期：2014-11-07 00:00:00

abstract：:Recently, there has been an increased interest in flattening-filter-free (FFF) linear accelerators. Removal of the filter results in available dose rates up to 24 Gy min(-1) (for nominal energy 10 MV in depth of maximum dose, a source-surface distance of 100 cm and a field size of 10×10 cm2). To guarantee accurate rel...

journal_title：Physics in medicine and biology

authors： Lang S,Hrbacek J,Leong A,Klöck S

更新日期：2012-05-07 00:00:00

abstract：:In order to enable a detailed analysis of radio frequency (RF) absorption in the human middle and inner ear organs, a numerical model of these organs was developed at a spatial resolution of 0.1 mm, based on a real human tissue sample. The dielectric properties of the liquids (perilymph and endolymph) inside the bony ...

journal_title：Physics in medicine and biology

authors： Schmid G,Uberbacher R,Samaras T,Jappel A,Baumgartner WD,Tschabitscher M,Mazal PR

更新日期：2007-04-07 00:00:00